This application relates to medical devices and more particularly to medical devices which have dimensions small enough to pass through the central passage of a scope.
The type of medical device herein contemplated includes an elongated canula assembly having a distal end which carries a medical instrument with movable parts constructed and arranged to be inserted into a patient and a proximal end which carries a moving assembly constructed and arranged to be retained exteriorly of the patient.
Our issued U.S. Pat. Nos. 5,906,622 and 5,924,175 illustrate medical instruments in the form of an annularly extending and retracting gripping and releasing assembly, as, for example, a kidney stone extractor instrument. The patents disclosed embodiments of a miniature size sufficient to pass through a three French central passage of a scope. The mechanism of the of the instrument includes a plurality of operative elements which are (1) longitudinally fixed and of generally tubular configuration and (2) longitudinally movable and of elongated configuration suitable to move within the tubular configuration of element (1). Each longitudinally fixed tubular element forms a part of one of a plurality of cooperating medical instrument structures which extend from the confined proximal end thereof to a distal end spaced longitudinally outwardly of the proximal end. Each longitudinally movable elongated element is movably disposed within a longitudinally fixed tubular element forming a part of one of the cooperating medical instrument structures and has a distal end disposed (1) outwardly of the distal end of the one longitudinally fixed tubular element and (2) fixed relative to an adjacent one of the plurality of medical instrument structures at a position spaced longitudinally outwardly of the confined proximal end thereof. In the embodiments disclosed in the patents, the cooperating medicate instrument structures constituted three (or more than three) annularly arranged fixed tubular elements so that the movement of the movable elongated elements within the tubular members and their fixture with respect to the adjacent tubular elements resulted in the annular expansion and contraction of the distal ends of the fixed tubular members. A distinct advantage of the arrangement is that both expansion and contraction are effected positively by the movable elongated elements. While all of the illustrated embodiments in the patents include three or more annularly arranged cooperating medical instrument structures, the principle of operation and the advantages of positive expansion and retraction are applicable to medical instruments which simply have two opposed cooperating medical instrument structures.
Accordingly, it is an object of the present invention to provide a medical device comprising an elongated canula assembly having a distal end constructed and arranged to be inserted into a patient and a proximal end constructed and arranged to be retained exteriorly of the patient. The canula assembly has a medical instrument assembly on the distal end thereof and a moving assembly on the proximal end thereof. The medical instrument assembly comprises a plurality of cooperating medical instrument structures having proximal ends confined peripherally at a position of confinement and distal ends movable toward and away from each other. At least one of the cooperating medical instrument structures includes a longitudinally fixed tubular elements fixed at the proximal confined end thereof having a free end spaced from the position of confinement. The tubular element has a movable elongated flexure element extending therethrough having a distal end disposed outwardly of the free end of the fixed tubular element and fixed with respect to a cooperating medical instrument structure at a position thereon spaced from the confined proximal end thereof. The moving assembly includes fixed structure having moving structure movably mounted thereon spaced from the confined proximal end thereof. The moving assembly includes fixed structure having moving structure movably mounted thereon positioned and configured to be manually moved. The canula assembly includes an elongated longitudinally fixed transversely flexible guide structure extending between the fixed structure of the moving assembly and the proximal end of the fixed tubular element and an elongated flexible moving member disposed in movably guided relation to the elongated longitudinally fixed transversely flexible guide structure connected between the movable structure of the moving assembly and the movable flexure element so that when the moving structure is manually moved in one direction the distal ends of the cooperating medical instrument structures are moved away from one another and when the moving structure is manually moved in an opposite direction the distal ends of the cooperating medical instrument structures are moved toward one another.